Mineral oil compositions containing amidic acids or salts thereof



United States Patent MINERAL OIL COMPOSITIONS CONTAINING AlVIlDIC ACIDS OR SALTS THEREOF Herschel G. Smith, Wallingford, and Troy L. Cantrell, Drexel Hill, Pa., and John G. Peters, Audubon, N. J., assignors to Gulf Oil Corporation, Pittsburgh, Pa., a corporation of Pennsylvania No Drawing. Application October 2, 1952, Serial No. 312,844

16 Claims. (Cl. 25233.6)

This invention relates to mineral oil compositions and particularly to improved mineral oil compositions which comprise a major amount of a mineral oil and a minor amount of an improvement agent sufiicient to confer thereupon useful and advantageous properties, such as rust or corrosion prevention and other desirable properties.

With the advancing refinement of various devices in which mineral oils of the fuel and lubricant type are employed, increasingly severe demands have been made of the particular fuels or lubricants used therein. As is well known in the art, the straight or uncompounded" mineral oils are often deficient in one or more respects for the particular use to which they are put. For example, a high resistance to rust or corrosion is important in the case of fuels or lubricants which are required to function in the presenceof water. Fuels or lubricants for internal combustion engines and for gas or steam turbines and lubricants for various bearing members which are subjected to moisture are examples of mineral oil products which may operate under conditions highly conducive to rusting or corrosion.

Faflure to provide sufficient resistance to rust or corrosion by the mineral oil may result in extensive wear or damage tov costly, highly machined moving parts. To overcome this and other deficiencies various agents known as addition agents, additives, or improvement agents are commonly incorporated into the particular mineral oil to be used.

An object of this invention is the provision of mineral oil compositions having improved rust and corrosion inhibiting properties as well as other desirable characteristics. Other objects appear hereinafter.

These and additional objects are accomplished by the present invention which includes new mineral oil compositions containing a major amount of a mineral oil and a minor, corrosion inhibiting amount of an agent having the formula R1 R2 -N-CHr-N-Ri x z o-o-- (l where CifiG embodiments of the invention and matters ancillary thereto have been described. It is understood that these are by way of illustration only and are not to be considered as limiting.

The various mineral oils in which the novel improvement agents may be incorporated include both the fuel and lubricant type. Examples of fuel type mineral oils are gasoline, kerosene, diesel fuel, and furnace oil. Examples of lubricant type mineral oils are engine oils, turbine oils, and greases. The invention also includes mineral oil compositions where the mineral oil constituent is not employed as a fuel or lubricant but merely as a solvent vehicle. Exemplary of this type of composition are light naphtha or like mineral oil solvents containing the novel additives of this invention.

The improved mineral oil compositions of the invention are conveniently prepared by simply dissolving a minor proportion, sufiicient to confer corrosion-inhibiting properties on the composition, of the desired oil soluble improvement agent in the particular mineral oil to be used. Elevated temperatures may be employed to assist in dissolving the additive. Alternatively, the compounding of our mineral oil compositions may involve preparation of the additive in a mineral oil solvent to provide a concentrate of the additive. This concentrate may be dissolved subsequently in the particular mineral oil to be used. The latter method is preferred in view of the relative ease in obtaining a solution.

The novel additives of this invention, the chemical nature of which has been indicated above, may be conveniently designated as amidic acids or the substantially neutral salts thereof.

The preparation of these additives has been described fully in copending application Serial No. 312,843, filed in the names of Smith, Cantrell and Peters on October 2, 1952. For the sake of clarity, certain preferred methods of preparation have been set forth briefly below.

The preparation of the amidic acids of this invention involves the partial amidation at conventional conditions of a cyclic dicarboxylic acid anhydride with an N,N'-

substituted methylene diamine having the formula r r N-C Ha-N-Ra standpoint of color, purity, and oil-solubility.

Any cyclic dicarboxylic acid anhydride is suitable for the purposes of this invention. These substances, as known in the art, are capable of reacting with primary or secondary amines to form amides.

Cyclic acid anhydrides of aliphatic dicarboxylic acids are formed from acids having two carboxyl groups attached to adjacent carbon atoms or to carbon atoms separated by a third carbon atom. Examples of such acids are maleic, succinic, and glutaric acids. Alkyl substitution products of these acids, such as isopropyl succinic acid (pimelic acid) behave similarly as the unsubstituted acids. Aromatic dicarboxylic acid anhydrides such as O-phthalic acid anhydride are also suitable for the purposes of the invention.

The conditions of amidation may vary somewhat according to the particular starting materials. The reaction takes place satisfactorily at temperatures of about 200 F. Somewhat higher or lower temperatures may be used with no undesirable results. The reaction is normally complete in from about 60 to about 120 minutes, depending largely on the temperature employed.

The amidation reaction may be conducted simply by mixing equimolar proportions of the acid or anhydride and the N,N'-substituted methylene diamine and heating,

' or alternatively, by first dissolving the reactants in a solvent (preferably a mineral oil solvent) and conducting the reaction in solution. The amidic acid product may be recovered in the form of a solution, or alternatively,

the solvent may be removed by evaporation to provide gthe-amidic acid per se.

When a metal salt of the amidic acid is the desired final product, the amidic acid need not be prepared se arately, but the methylene diamine, the dicarboxylic acid anhydride and a suitable metal hydroxide can all be reacted simultaneously. Thus, the alkali metal hydroxides and the alkaline earth metal hydroxidescan be'added 1 directly to the reacting mass in the form of an aqueous solution or slurry. In the case of certain diflicultly reacting metal hydroxides, the alkali metal salt of the Illustrative of metals which give desirable amidic acid salts according to this invention are sodium, lithium, potassium, barium, calcium, magnesium, strontium, lead, copper, iron, nickel, mercury, zinc, bismuth, aluminum, chromium, tin, manganese,.silver and cadmium.

Amine or ammonium salts of the novel amidic acids are also included in the invention. These can be prepared, for example, by simple reaction of the amidic acid with an appropriate nitrogen base,'such as a primary, secondary or tertiary amine,. or ammonium hydroxide. The neutralization reaction occurs easily at room temperature or moderately elevated temperature.

The particular N,N'-substituted methylene diamines employed in the amidation reaction described above are prepared conveniently by condensation of a suitable primary amine or mixture of primary and secondary amines with formaldehyde in the proportion of 2 mols of amine to 1 mol of formaldehyde. Where a mixture of primary and secondary amines is employed, at least one-half of the mixture on a molar basis should be primary amines.

As will be evident from the generic formula for the methylene diamine set forth above, thesubstituents of the primary and secondary amines employed in the condensation reaction may vary widely. Thus, primary or secondary amines having alkyl, alkenyl, cycloalkyl, aryl, alkaryl, and aralkyl substituents are suitable. Illustrative of primary, acyclic, aliphatic amines suitable for condensation with formaldehyde to form N,N'-substituents methylene diamines are alkyl amines having at least 8 carbon atoms, and preferably from 8 to 26 carbon atoms, such as octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, octadecyl and eicosyl. The corresponding alkenyl amines such as octenyl, nonenyl, undecenyl, tetradecenyl, octadecenyl (oleyl) and eicosenyl amines are also suitable. The primary alkyl or alkenyl amines having more than 26 carbon atoms, such as wax amines, are also suitable. Examples of suitable primary cycloalkyl amines include cyclopentyl, cyclohexyl, cycloheptyl amines and the like. Aniline, alphanaphthylamine and beta naphthylamine are illustrative of suitable aryl amines, just as the toluidines and xylidines are illustrative of suitable alkaryl amines. Satisfactory aralkyl amines are exemplified by benzylamine, betaphenylethylamine and the like.

Secondary amines corresponding to all these classes of amines also produce advantageous compounds and include not only amines containing substituents from "the' same class such as diphenylamine, phenyl alphanaphthylamine and dicyclohexvlamine, but also amines containing substituents from different classes such'as octyl-phenyl amine and the like. N;lT-oleyl propanol amine and N,N-dodecyl' ethanol amme.

In the class of primary alkyl amines the use of commercial mixtures of fatty amines ispreferred. One commercially available mixture of amines is the so.-called cocoamine which is prepared by converting the mixed acids of coconut oil to the corresponding amines by well known methods. average molecular weight of 200-210 and contains pre- Other suitable secondary amines are The commercial cocoaminehas an.

of 400 F. are undesirable, since they may result in the formation-of color-forming bodies andinsome decomposition of products.

Thus, the novel additives of this invention are preferably prepared by condensation of the desired primary amines or mixtures of primary or secondary amines with formaldehyde in the proportion of 2 mols of amine to 1 mol offormaldehyde ata temperature of about'160"-- F., followed by dehydration of the product at-a temperature of between about 260 F. and 400 F. To the dehydrated product is added a dicarboxylic. acid anhydridevin an" amount sufiicie'nt to provide equimolar' proportions of acid 'anhydride-and the methylenediaminex Heat of'a degree sufficient to effect the amidation is employed. Normally, a temperature of about 200 F. is satisfactory. The salts' of the amidic acid may be prepared by subsequent, or in many instances, simultaneous neutralization of the amidic acid with a suitable basic material.

The resulting product either alone or in the form of a'solutionconcentrate may .thenbe incorporated in the desired mineral oil in a minor proportion, sufficient to confercorrosion inhibiting propertiesand other desirable Normally from about 0.01 l per cent to about 1.0 per cent of the additive by weight of" properties upon the latter.

the compositionis sufiicient for this purpose.

The following illustrative examples will serve to illus-- trate more clearly the preparation of the novel amidic acids and salts thereof included in this invention, as well as the desirable results obtained by their use in various mineral oils.

Example '1 Four mols of cocoamine. were introduced into a reac- 4 droxide were then dispersed in an equal weight of lubricating oil. Two mols of phthalic anhydride, the acid anhydride of O-phthalic acid, were then added and the temperature held at 200 F. for two hours. The temperature was. subsequently raised to 270' F. to dry the product and the-product was filtered. The mineral oil solution of the product formed by this process had the following properties:

dominantly lauryl amine together with lesser proportions 1 of various homologues thereof. By coco radical as used herein is meant the mixture of coconut oil fatty acid alkyl groups present as N-substituents in commercial cocoamine.

The condensation of the amines described above with Temperatures -materially in "excess Sp. gr., 60/60 F 0.8969 Viscosity, SUV, F'. 279 Color, NPA 1.75 Neutralization No 1.74 Ash, per cent 1.6 0 pH value; 9.9

The salt formed in this example had the following formula:

where R represents the coco radical or residuew-of the cocoamine.

The salt formed as described above except using a volatile solvent instead of alubricating oil solvent, exhillaited the following characteristics after removal of so vent.

Characteristics -Q Clear solid.

Molecular weight 1200.

Ash, per cent by weight 4.66.

Example II The salt described in'Example I was also-formed by" metathesis. According to this method, 4 mols of coco-1 amine were introduced into a reaction vessel, and-2 mols of formaldehyde in a 37 per cent by weight aqueous solution were slowly added with constant stirring, while maintalning'the temperature below F. When the reactlon was completed, after about 60 minutes, the temperature was raised to 350"" F. to remove all water, both. that'added with'the formaldehyde and that formed with the reaction. The methylenezdiamine product so formed was dispersed in an equal weight of lubricating oil and 2 mols'of a 40 per cent aqueous solution of sodium hydroxidewere added. Two mols of phthalic anhydride were added and the temperature held at 200 F. for two hours. Then 1 mol of an aqueous solution of calcium chloride was added continuing agitation for two hours. The temperature was subsequently raised to 270 F. to dry, and the product was filtered to remove the salts and extraneous material. The mineral oil solution of the product formed by this process had the following properties:

Sp. gr., 60/60 F 0.8969 Viscosity, SUV, 100 F 279 Color, NPA 1.75 Neutralization No. 1.74 Ash, per cent 1.6 pH value 9.9

Example 111 In an open enamel lined reaction vessel, 1260 parts by weight ofcocoamine and 255 parts by weight of a 37 per cent by weight aqueous formaldehyde solution were reacted for about 60 minutes, while maintaining a temperature below about 160 F. The temperature was then raised to 300 F. in order to remove the water which was formed and which was added with the formaldehyde. The mixture was subsequently cooled to 180 F. and 444 parts by weight of phthalic anhydride were added. The reaction was allowed to proceed for half an hour at 200: F. The product obtained had the following properties:

The amidic acid formed in this example had the following formula:

CH ll where R represents the coco radical or residue of the cocoamine.

Example IV .In an enamel lined reaction vessel, 1260 parts by weight of cocoamine and 255 parts by weight of a 37 per cent by weight aqueous formaldehyde solution were reacted for about 60 minutes, while maintaining a temperature below about 160 F. The temperature was then raised to 300 F. in order to remove the water of reaction and that in which the formaldehyde had been dissolved. The mixture was subsequently cooled to 180 F. and .294 parts by weight of maleic anhydride were added. The temperature was held at 160200 F. until completion of the reaction, i. e., about 90 minutes. The product had the following properties:

Characteristics Dark-colored liquid. Molecular weight 530.

Neutralization No 105.8.

Gravity, API 20.9.

Viscosity, SUV, 210 F 80.2.

Color, NPA 3.0.

The amidic acid formed in this example had the formula:

Where R represents the coco radical or residue of the .cocoamme.

Example V Into an-enamel lined reaction vessel, 4 mols of dicyclohexylamine and 4 mols of a 37 per cent aqueous solution of formaldehyde were introduced. The mixture was-re- 5 Flas Characteristics Clear colored, low-meltingsolid of fat-like consistency. Molecular weight 551.

Neutralization No 101.7. Gravity, API 15.8. Color, NPA 7.5.

The amidic acid formed in this example hadqthe formula:

where R represents the coco radical or residue of the cocoamine.

As will be obvious to one skilled in the art, any of the primary amines .ormixtures of primary and secondary amines described also can be utilizedto form the methylene .diamines according to the procedure described in Examples I-V, inclusive. Also, any of the previously described class of acid anhydrides can be substituted in the above examples with satisfactory results.

The amidic acids and salts of this invention are useful 1n many arts, particularly thosewhere corrosion and rust inhibiting properties are desired. Their solubility in .oil permits their use in lubricating oils where'it is desirable to inhibit rust and corrosion. Moreover, these compounds produce excellent results when used in lubricating oils which encounter severe operating conditions. The eilectiveness of our new compounds as mineral oil additives is clearly illustrated vby the following examples.

Example V] Treated Untreated Oil Oil Gravity, API visclosityfi SUV:

210 F Viscosity Lndex.

r, NPA Carbon Residue, percent. Precipitation N 0 ur, B, percent Copper Strip Test, 212 F 3 Corrosion Test, ASTM D 66547 T, Distilled Example VII An improved cup grease was prepared by treating a conventional cup grease with 0.3 per centby weight of the product prepared according to Example 1 above. The properties of the untreated cup grease and the cup grease improved with the additive of this invention are illustrated below:

Untreated Grease Treated Grease Sp. Gr., 60l60 F Melting Point, F., I-Iawxhurst Dropping Point, F., ASTM D 566-42" Flfl/GPfint, F., Navy Dept. Specifi Corrosion Test, Method 423, Gulf, cc. Syn.

Sea Water, 140 F., 12 Days, Steel Strip, Appearance.

Example Vlll An improved diesel fuel was prepared by treating a diesel fuel (light) with the additive prepared in accordance with Example I above in the ratio of 100 pounds of the additive per 1000 barrels of fuel. The properties of the untreated and treated diesel fuel appear below:

Untreated Treated Diesel Diesel Fuel Fuel (Light) (Light) Gravity, API 42.6.- 42.5. Viscosity, SUV, 100 F, 31.6. Flash, P-M, F 146. Clou F 40. Pour, F 45. Color, Saybolt. +19. Doctor good. Odor normal. Sulfur, L, Percent Water A: Sediment, Percent Copper Strip Test, 122 F., 3 Hr Corrosion Test, Method 412, Gull 4 cc. Water,

36 cc./Oil, 12 Days:

Steel Strip, Appearance rusted-.." bright. Area Rusted, Percent 100 0.

Example IX An improved turbine lubricating oil was prepared by treating a turbine lubricating oil base with 0.1 per cent by weight of the addition agent prepared according to Example IV above. The properties of the unimproved turbine oil and the improved turbine oil were as follows:

Unimproved Improved Oil Oil Gravity, API Viscosity, SUV:

Vi m ity Index Corrosion Test, ASTM D 665-47 T, Distilled Water:

Steel Rod, App r n ruste bright. Area Rusted, Percent 100 0. Neutralization N o 0.02- 0.03.

Example X Unimproved Improved Oil Oil Gravity, API 31.7 31.3. visclosigy, SUV:

Viscosity Index Color, NPA Corrosion Test, ASTM D 665-47 T, Distilled Water:

Steel Rod, Appearance rusted bright. Area Rusted, Percent.. 100 0.

Example XI An improved turbine lubrication oil was prepared by treating a turbine lubricating oil base with 0.1 per cent by weight of the addition agent prepared according to Example III above. The properties of the unimproved turbine and the improved turbine oil were as follows:

Unimproved Improved Oil Oil Gravity: API..- 31.7-. 31.7. Viscosity, SUV:

210 F 43.8" 43.8. Viscosity Index. 110. Color, NPA 1.25-- 1.25. Corrosion Test, ASIM D 665-47 '1, Distilled Water:

Steel Rod, Appearance rusted bright.

Area Rusted, Percent 100 0. Neutralization N n 0.02. 0.04.

A description of the procedure to be followed in Gulf Corrosion Test, Method 412, mentioned in Example VIII above, is found in U. S. Patent No. 2,378,442, to Smith et al., at page 4, column 1, lines 35 to 53, inclusive. A description of Gulf Corrosion Test, Method 423, mentioned in Example VII above, is presented in our 8above-identified copending application Serial No. 312, 3.

From the foregoing it is evident that the described amidic acids and salts thereof can be used in a large number of compositions to improve the rust and corrosion inhibiting properties thereof. Thus, in addition to mineral lubricating oils, greases and diesel fuels, the described additives can be employed in conjunction with gasoline, furnace oil, slushing oil and other oils. As has been indicated, the described amidic acids and salts thereof can also be incorporated in mineral oil products such as light naphtha, which are not employed as either a fuel or a lubricant. In such instances our compositions find use in the coating art, whereby a metallic article subject to corrosion is brushed, dipped or sprayed with the composition comprising the solvent vehicle and the additive. Subsequent evaporation of the solvent leaves an adherent corrosion resistant coating of the additive on the metallic article.

It is to be understood that the improved mineral oil compositions of this invention can be additionally improved by incorporation therein of other known additives in order to confer other desirable properties such as increased resistance to oxidation, increased stability, etc. thereon. Thus, there can be added viscosity index improvers, thickeners, bearing corrosion inhibitors, antioxidants, dyes, etc.

Resort may be had to such modifications and variations as fall within the spirit of the invention and the scope of the claims appended hereto.

What we claim is:

1. A mineral oil composition comprising a maior amount of a mineral oil and a minor, corrosion inhibiting amount of an agent having the formula:

where represents the acyl residue of a dicarboxylic acid capable of forming a cyclic acid anhydride, R1 and R2 represent radicals selected from the group consisting of acyclic aliphatic radicals having at least eight carbon atoms, cycloalkyl, aryl, alkaryl, and aralkyl radicals, R3 is selected from the group consisting of hydrogen and a radical of the same kind as R1 and R2, Z is selected from the group consisting of hydrogen and a salt-forming radical, and n is an integer equal to the valence of Z.

is the acyl residue of phthalic acid.

8. The composition of claim 1 where is the acyl residue of maleic acid.

9. A mineral oil composltion comprising a ma or amount of a mineral oil and a minor, corrosion inhibiting amount of an amidic acid having the formula:

where R is lauryl.

10. The composition of claim 9, where the amidic acid is present in the amount of from about 0.01 per cent to about 1.0 per cent by weight of the composition.

11. A mineral oil composition containing a major amount of a mineral oil and a minor, corrosion inhibiting amount of an amidic acid having the formula:

o-orr where R is lauryl.

12. The composition of claim 11, where the amidic acid is present in the amount of from about 0.01 per cent to about 1.0 per cent by weight of the composition.

13. A mineral oil composition comprising a major amount of mineral oil and a minor, corrosion inhibiting amount of an amidic acid having the formula:

where R is lauryl.

14. The composition of claim 13 where the amidic acid is present in the amount of from about 0.01 per cent to about 1.0 per cent by weight of the composition.

15. A mineral oil composition comprising a major amount of a mineral oil and a minor, corrosion inhibiting amount of a salt of an amidic acid having the formula:

0 0 g C "a n where R is lauryl.

16. The composition of claim 15 where the salt is present in the amount of from about 0.01 per cent to about 1.0 per cent by weight of the composition.

References Cited in the file of this patent UNITED STATES PATENTS 2,191,738 Balle Feb. 27, 1940 2,349,817 Farrington et a1 May 30, 1944 2,408,103 Smith et al Sept. 24, 1946 

1. A MINERAL OIL COMPOSITION COMPRISING A MAJOR AMOUNT OF A MINERAL OIL AMD A MINOR, CORROSION INHIBITING AMOUNT OF AN AGENT HAVING THE FORMULA: 